In semiconductive devices, interconnections and the like are used for providing electrical connections between components. A widely used material for forming such interconnections and the like is tungsten (W). Typically, before the formation of tungsten, a barrier layer may be conformally formed on an underlying layer for preventing deterioration due to diffusions of elements. Then, a tungsten layer may be deposited on the barrier layer. After removing the redundant portions of the tungsten layer, the interconnections can be provided. In the cases of forming interconnections and the like using other conductive materials, barrier layers may also be provided.